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A coil has an inductance of 50 m H and a...

A coil has an inductance of `50 m H` and a resistance of `0.3Omega`. If a `12V` emf is applied across the coil, the energy stored in the magnetic field after the current has built up of its steady state value is

A

`40J`

B

`40mJ`

C

`20J`

D

`20mJ`

Text Solution

Verified by Experts

The correct Answer is:
A
`i_0=E/R=12/0.3=40A`
`U=1/2Li_0^2=1/2xx50xx10^-3(40)^2`
`=40J`
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DC PANDEY-ELECTROMAGNETIC INDUCTION-Level 1 Objective
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